There have been numerous patents granted on sectionalized structures that are useable as car top carriers and that may be assembled to form a boat starting at least as far back as U.S. Pat. No. 1,445,792 by A. E. Olsen and filed in 1922. However, we do not see wide use indicating that the past structures must be lacking in features of salability or useability.
We now have high strength sunlight resistant composite plastic material that is vacuum formable. Our invention, using a composite plastic material, covers a design with following desirable characteristics:
a) Vacuum formable to allow use of a low cost mold;
b) Expandable from two sections to three or more;
c) Utilizes one or more seats to give quite rigid but light weight boat;
d) Uses specially designed multi-use clamps in addition to interlocking dovetail joints to clamp sections solidly together at the point of maximum stress to allow continued use in rough water. The clamp also provides rigid adjustable oar lock positions and acts as a bumper on each side of the boat.
e) Has recessed handles in each segment to allow easy manipulation and provide for fastening segments together and fastening in place on top of a car. Large suction cups to protect the car top are used to anchor the segment to the car top.
f) Uses high strength light weight sunlight resistant plastic composite material that may be vacuum formed.
g) Segments that may be used for uses such as a watering trough, wading pool or decorative pool and also used as part of a boat or carrier container.
This design provides low cost movability to form a heavy duty expandable boat with multi-use segments with safe but simple connections, allows storage in a limited space, and fills a need for the casual user with limited budget.
We consider U.S. Pat. No. 4,718,587 by Roberts issued Jan. 12, 1988 as the closest prior art. There are important differences. Roberts uses a dovetail joint only to connect two segments. This joint is similar to ours, but quite different in that we use a pair of clamps with pressure pads in addition to this joint to clamp segments rigidly together at the top and at the very bottom of the boat which is the point of maximum stress. Further, Roberts design lacks handles for ease of handling; is not expandable and would not appear to be suitable for uses such as a wading pool, etc. Our design is therefore more useable overall and being moldable should be cheaper to make.